Technology made driving f1 cars less brutal on the body. To start of in the first seasons a lot of stuff was unknown, for example some drivers wanted oxygen bottle so they wouldn't pass out while carefully leaving a fire. Others preferred instead to have the car to be the most easy as possible to leave, if a fire happened.

Now there is also head support, while drivers back then had to just use their muscles to hold their head in place.

The list goes on... but it still is an athletic sport. When Nico Rosberg decided to win the championship, he had to heavily change his routine to so way more fitness training than he was used to. After he won the championship and immediately retired, he hinted that one of the reasons for retirement is that he didn't want to continue with the heavy body training.